def get_queryset(self):
    pk = self.kwargs['pk']
    not_restriction = Ejemplo.objects.filter(not_restriction=True, id=pk)

    if not_restriction.count() == 1:
        return [Dispositivos(id='not_restriction', serie='not_restriction')]
    return Dispositivos.objects.filter(is_active=True, device__config_element__agent__registration_code=pk)